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Homeserve - Plumbing glossary
Category: General technical and industrial > Plumbing
Date & country: 16/12/2007, UK
Words: 167


ABS
(Acrylonitrile Butadiene Styrene) A Rigid black plastic pipe used for drain, waste and vent pipes.

Access Panel
An opening in the wall or ceiling near the fixture that allows access for servicing the plumbing or the electrical system.

Acrylic
A glassy thermoplastic cast and moulded shapes to form the surface of bathtubs, whirlpools and shower bases.

Activity Space
The ideal sized space in front of and to the sides of the bath, basin, WC and bidet to allow standing / sitting room and room to move.

Adaptor
A fitting that unites different types of pipe together, e.g. ABS to cast iron pipe.

Airlock
Trapped air in pipe-work where, due to its layout, the air cannot escape naturally. This usually results in zero or very little flow through the pipe.

All-in-One Power Shower
A product which houses a pump and some form of integrated shower control. It needs a low pressure cistern fed supply of stored hot and cold water.

Automatic Air Vent
A mechanical device with an integral float that releases air when the water level drops within it. It is normally fitted at the highest point of a plumbing system to release trapped air.

Back Siphoning
A backflow caused by the siphonage of liquid from a cistern or appliance into the pipe feeding it, which may lead to a contamination of the water supply.

Back-to-Wall
Some bathroom furniture is specially designed to conceal the cistern, support the basin and hide the pipe-work, hence creating storage space. The WC and bidet may be described as 'back-to-wall'. This can look very streamlined and can be an effective and economical use of space in a small bathroom.

Backflow
Means a flow in a direction contrary to the intended normal direction of flow, usually caused by siphoning.

Backflow Preventer
A device used to prevent backflow. In some areas, plumbing codes require a backflow preventer.

Ball Cock
AKA Float Operated Valve. A valve used to control the flow of water into a tank or cistern, the valve being controlled by a float on the surface of the water in the tank/cistern.

Bar
A unit of measurement of water pressure - one bar is approximately equivalent to a column of water 10m high or 14.5 lbf/in,2 or 100 kPa.

Basin
A circular vessel with sloping sides used to hold water for washing.

Bidet
Used for washing your posterior. It is floor mounted, usually next to a toilet.

Body Jets
Wall mounted sprays usually installed in multiples.

Bonding Clamp
A metal strap fastened to a pipe or a fitting to enable electrical earth bonding.

Bottle Trap
A form of trap for basins and sinks etc - usually in a cylindrical form where the bottom can be unscrewed from the body for cleaning etc.

Box Rim WC
The rim of the WC pan that carries the flushing water is a tube with accurately positioned holes in the underside. Bowl cleaning is superior because the water flow is used more efficiently and the operation is quieter. Not all WC's have a box rim - some have 'open rim'.

Bridge Mixer Tap
Stylish lever sink bridge mixer tap with quarter turn operation, suitable for the less able.

Built-in
A valve installed where the body is recessed in the wall.

Bulkhead Fitting
See Wall Outlet Connector.

Capillary Connector
A pipe coupling with a tight fit on the pipe, the gap being filled with solder once heated to provide a watertight seal. Some couplings incorporate a solder ring (also known as a Yorkshire fitting), while others need solder applied once the joint has been heated. The joints are not reusable. Available as a straight 'T', elbow and other configuratio…

Cast Iron
Heavy metal formed by casting in moulds.

Ceramic Disc Taps - Technology
Taps which can be turned on or off with just a quarter turn. Ceramic discs inside the tap create a watertight seal and drip-free 'off' position

Ceramic Disc Valve
A type of valve that relies on two-part revolving discs in a sealed cylinder. Each disc has a port in it that, when aligned with the other, will control water flow (and sometimes temperature).

Ceramic Taps
Taps which use a rotating ceramic disc to control the flow of water - requiring only a quarter handle rotation to turn the flow on or off.

Check Valve
Means a plumbing fitting designed to allow water flow in one direction only.

Cistern
Means a fixed container for holding water at atmospheric pressure, normally applied to the local water storage to flush a WC. It is normally fitted with a float operated valve and warning pipe.

Cleanout
A plug in a trap or drain pipe that provides access for the purpose of clearing an obstruction.

Close Coupled WC
A pan/cistern combination where the underside of the cistern rests directly on the back of the WC bowl creating a compact unit with low overall height. Generally the cistern is operated by a lever mounted on the front of the cistern or (more modern) a push button on the cistern top cover. Some contemporary designs appear almost like a single item.

Cold Water Storage Cistern
A fixed container for holding water at atmospheric pressure usually used for providing a feed to a vented domestic hot water cylinder. It can also be used to provide a vented cold supply to terminal fittings.

Cold Water Storage Tank
A fixed container for holding water at atmospheric pressure usually used for providing a feed to domestic cold water and/or to a vented domestic hot water system.

Compression Connector
A pipe coupling using threaded nuts to compress an 'olive' on the pipe to provide a watertight seal. More expensive than capillary joints but are easy to fit and generally reusable. Available as straight, 'T', elbow and other configurations.

Compression Fitting
A sealed pipe connection without soldering. As you tighten a nut on one fitting, it compresses a washer around the second pipe, forming a watertight closure.

Compression Valve
Works by lowering or raising a stem. By turning the tap it causes the stem to drop or rise, allowing water to pass through the valve.

Coupling
A straight fitting that joins two pieces of pipe.

Cross Flow
The water flow from one side of a hot/cold water mixer to the other, possibly leading to a contamination of the water supply.

Cylinder Flange
A plumbing fitting which can be fitted to a hot water cylinder to provide a dedicated hot water supply to a terminal fitting.

Deck Mounted Taps
Taps designed to mount on the edge of the basin or bath (as opposed to being wall mounted).

Distributing Pipe
Means any pipe (other than a flush pipe or warning pipe) conveying water from a cold water storage cistern.

Diverter
Valves which have one inlet and direct water to one of two outlets. Diverters are normally used with shower risers, hand showers, and kitchen taps.

Double Check Valve
Two check valves in series with a test point between the two.

Double Ended Pump
See Twin Pump.

Double Pole Switch
An electrical switching device in which the continuity of both the mains live and neutral is broken upon the action of the switch giving a contact separation of at least 3mm.

Downstream
In the same direction as flow away from a given point of reference. (With the flow of water from a given point of reference)

Dual Flow taps
Hot and cold supplies are of different pressures. They come from a single spout but are not pre-mixed - beware of scalding.

Dual Flush
A WC cistern offering the option of a water saving or full volume flush. Current UK flush volumes are 4 and 6 litres of water.

Duty Cycle
The recommended operating time of the product expressed as time 'on' and a time 'off '. A continuously rated pump can be operated non stop.

Dynamic Pressure
The water pressure in the pipe work to a fitting whilst flow is taking place.

Earth Bonding
A legal safety requirement to have all metal parts within a plumbing system connect to earth to prevent them becoming electrically dangerous.

Earth Bonding Strap
A metal strap used to achieve 'earth bonding' by joining the metal pipes and fittings together to provide an electrical earth path.

Elbow
Angled fitting that changes the direction of the water line.

Enamel
An opaque vitreous composition applied to the surface of metal fixtures such as cast iron tubs and sinks.

Expansion Pipe
See Vent Pipe.

Expansion tank
A tank which will accommodate the expansion of water within a system as it heats up or to absorb pressure shock waves to reduce water hammer. May be open or sealed depending on whether the system is vented or sealed.

Expansion Vessel
A vessel which contains a device either to accommodate thermal expansion of water or to absorb the pressure shock waves of water hammer.

Fibreglass
Glass in a fibrous form used in making the body of bathtubs.

Fixed Shower Head
An over head fixed height shower head.

Fixture
A broad based term usually referring to sinks, tubs, toilets, and basins.

Float Operated Valve
AKA Ball Cock. Is a valve used to control the flow of water into a cistern, the valve being controlled by the level of water in the cistern.

Flow Limiter
See Flow Regulator.

Flow Pressure
See Dynamic Pressure.

Flow Regulator
A device with moving parts which responds to variable inlet pressures to control flow at a reasonably constant rate. These are subdivided into two types a) Fixed - manufactured in a range of predetermined flow rate settings. b) Variable - manually adjustable to provide different flow rate settings.

Flow Restrictor
A device with no moving parts which restricts flow. Unlike a flow regulator it does not keep a constant flow when the supply pressure varies.

Flow Switch
Electro mechanical device that senses a small flow of water and energises an electrical contact.

Flush Fit
See Built-in.

Free Outlet Flow Rate
See Open Outlet Flow Rate.

Gate valve
A hand operated on/off valve permitting water flow in either direction.

Gel Coat
Material used to form the surface of some fibreglass bathtubs or showers; it is a coloured, polyester resin.

GPM
Gallons per Minute. Unit of measurement by which flow rates of taps and showerheads are measured and regulated.

Hand Shower
A showerhead designed with a flexible shower hose that is attached to the water supply. It can also be termed a shower handset.

Handset
See Hand Shower.

Handset Holder
See Wall Bracket.

Header Tank
See Cold Water Storage Cistern.

High Level Cistern
A cistern mounted high on the wall and connected to the WC pan by a long flush-pipe, the flush is powerful and operated by a pull-chain and handle.

Hose Restrainer
A device which restrains a shower hose to prevent immersion of the hand shower.

Hose Retaining Ring
See Hose Restrainer.

ID
Inside Diameter. Diameter measurement from the inside of a pipe. Commonly used for sizing pipe.

Impeller
The internal part of the pump that is driven by the motor, and is used to move the water.

Inlet
Opening providing an entrance or intake.

Inlet Pump
See Twin Pump.

Integrated Power Showers
See All-in-One Power Showers.

Low level Cistern-WC
A cistern mounted on the wall just above the WC pan with a short flush pipe. Generally the cistern is operated by a lever mounted on the front of the cistern or (more modern) a push button on the cistern top cover.

Maintained Pressure
See Dynamic Pressure.

Manual Mixing Valve
A device which mixes hot and cold water but does not compensate for variations in the temperature or pressure of the incoming water supplies and needs to be adjusted manually.

Mixer Shower
A simple shower using a valve to combine the domestic hot and cold water supplies to provide the required temperature and flow.

Mixer Taps
A tap with separate hot and cold inputs and having a single output. The inputs can be adjusted to give the required temperature and flow.

Mixing Valve
Mixes hot and cold water in the valve to get a set temperature before delivery.

Monobloc Taps
Hot and cold water are mixed and delivered through a single spout. The input pipes are smaller than 'normal' taps.

Negative Head
If the cistern is below the level of the shower head a gravity flow of water will not occur. A pump with special switching can be used to obtain a flow of water.

Nipple
A short pipe threaded on both ends installed between fittings.

Non-Return Valve
See Check Valve.

Offset Corner Bath
A design with one side longer than the other. Useful when a standard corner bath would be too large for the space available.

Olive
A brass or copper compression ring used in compression couplings.

Open Outlet Flow Rate
Maximum potential flow rate from a mixing valve without shower fittings being attached.

Outlet Pump
See Single Outlet Pump.

Overflow Pipe
A pipe connected from a tank or cistern to discharge any surplus water into an area without causing damage. Normally it will only come into use when there is a fault (e.g. a leaking valve). See also Warning vent.

Parking Bracket
See Wall Bracket.